1. Field of the Invention
The present invention relates to a UE location determination system for determining the location of a User Equipment (UE), and more particularly to a method for determining the location of a UE by means of Assisted Global Positioning System (AGPS) information.
2. Description of the Related Art
With the development of communication technology and the global spread of mobile communication networks, UE users want to receive not only a communication service but also various supplementary services using location information. Generally, because UEs may be carried by users and may perform communication wirelessly, communication carriers may provide UE users with various supplementary services by means of location information. Recent supplementary services using UE location information, which have been widely provided by communication carriers, include traffic information services, map download services, location information services, weather information services, emergency services, car navigation services, etc. These various supplementary services provided based on the location information of UEs will be referred to as location services. In order to receive these location services, the location of a UE must be exactly determined. Typically, a UE receives location assistance information, that is, AGPS information, receives exact GPS signals from GPS satellites, and then determines its own location by means of the GPS signals. The UE receives the AGPS information through a control plane such as an Radio Resource Control (RRC) of a Wideband Code Division Multiple Access (WCDMA) system, an Radio Resource Location Protocol (RRLP) of a General Packet Radio Service (GPRS) system and a control plane according to an IS-801 standard of a CDMA system, and determines its own location. Otherwise, the UE receives the AGPS information through a Secure User Plane Location (SUPL) using an Internet Protocol (IP)-based network, and determines its own location. FIG. 1 shows a UE location determination system for determining the location of a UE after receiving the AGPS information through the SUPL using the IP-based network.
FIG. 1 is a block diagram schematically showing the conventional construction of the UE location determination system using the AGPS information. Referring to FIG. 1, the UE location determination system includes a UE 10 and a SUPL Location Platform (SLP) 20. The UE 10, an object of location measurement, measures exact GPS signals using the AGPS information and transfers the measured GPS signals to the SLP 20.
The SLP 20 generates the AGPS information, transfers the AGPS information to the UE 10, computes the location of the UE 10 by means of values of the GPS signals measured by the UE 10, and determines the location of the UE 10 according to the computation result. This SLP 20 may include two parts, that is, an SUPL Location Center (SLC) 22 and an SUPL Positioning Center (SPC) 24. When location information is requested, the SLC 22 authenticates a requester having requested the location information, manages location information of UEs, performs an interface between the UE 10 and the SPC 24, and provides the location information requester with the final computed location of the UE 10. The SPC 24 generates the AGPS information for the UE 10 (object of location measurement), computes the location of the UE 10 after receiving the GPS information measured by the UE 10 through the SLC 22, and transfers location information for the computed location to the SLC 22. As a result, the location information is provided to the location information requester.
In the conventional location determination system as described above, an identifier (ID) of the same UE is used among the UE 10 and the SLC 22 and the SPC 24. For example, when a location request for a UE having a specific ID is received, the SLC 22 requests AGPS information for the UE by means of the UE ID. Also, the SPC 24 generates the AGPS information and transfers the AGPS information by means of the UE ID. That is, the UE ID is used between the SLC 22 and the SPC 24, so that transfer of the location information is accomplished.
When the location information is transferred through use of the UE ID between the SLC 22 and the SPC 24, messages exchanged between the SLC 22 and the SPC 24 may be leaked. Therefore, the location information for the location of the UE may be easily exposed because the UE ID is not secure. That is, in the conventional location determination system using the SUPL, the transfer of the location information between the SLC 22 and the SPC 24 through the use of the UE ID is not secure. As a result, a UE user's privacy may be compromised.